Ijv vector



(No Model.) 2 Sheets-Sheet 1 W. D. FORBES.

SCREW THREADING' MACHINE. No. 270,408. Patented Jan. 9,1883.

FIGJ

&

B Fla .2.

WITNESSES JJVV 1V 0R C 1am OMNWM N4 PETERS, PllolwLilhngmpher. Wasluimllnn. u. c.

(No Model.) 2 Sheets-Sheet 2. W. D. FORBES.

' SCREW THREADING MACHINE. No. 270,408. Patented Jan. 9, 1883.

WITIVE 5515s: 5

M W W M tlwrrap' STATES EPA-TENT @Frrea 'WILLIAH D. FORBES, or nemenroar, CONNECTICUT, assrenoa or one HALF TO RODERICK r. CURTIS, or SAME PLACE.

SCREW-'TH READING iVlACHiNE.

SPECIFICATION forming part of Letters Patent No. 270,408, dated January 9, 1853.

Application filed July 17, 1882. (No model.) Patented in England May 26, 1882, No. 2,508.

To all whom it may concern Be it known that I, \VILLIAM D. FORBES, a citizen of the United States, and a resident of Bridgeport, Connecticut, have invented certain Improvements in Die-Stocks, of which the following is a specification.

My invention relates to certain improvements in the die-stock for which Letters Patent of the United States No. 253,996 were granted to me on the 21st day of February, 1882, the objects of my present improvements being to dispense with the lead-screw of the patented device, and to provide a cutting-die adapted to support the end of the pipe to be I5 threaded.

In the accompanying drawings, Figure 1, Sheet 1, is a sectional view of my improved die-stock; Fig. 2, a front view of the same; Fig. 3. Sheet 2, a perspective vie\v,on a larger scale, of the cutting-die; Fig. 4, a front view of said die, and Fig. 5 a sectional view of the same.

The instrument is in many respects similar in construction to that described in the said 2 patent, A being the casing, to which is secured the pipe to be threaded, the pipe being shown by dotted lines in Fig. 1. projection, a, in which are bearings for an elongated pinion, B, the teeth of the latter o gearing into teeth on the periphery of the diecarrying ring 1), which can turn freely in the casing.

Cthe cutting-die E is confined to the ring D between an internal rib, b, and a screw-ling, (I;

but instead of adapting a flange on the ring D to a leading-screw in the casing, as in my said patented die-stock, I rely upon the threads of the cutters m to effect t-hefeeding of the said die onto thepipe as it-is being rotated. In order 40 to do this, 1 must impart end pressure to the ring D at the commencement of the cutting operation, and until two or three convolutions of the thread have been out upon the pipe, after which, the die being self-feeding, the end 5 pressure may be discontinued. In order toimpart the desired end pressure to the ring D, I prefer to use a lever, F, Fig. 2, which in the present instance is torked, each arm being pivoted to a stud, on the casing A, and carrying at the end a roller, j, which bears upon The casing has a the face of the ring D, so that by forcing the arm 00 of the lever outward the ring D will be moved inward and the die will be applied to the end of the pipe under pressure. This method of feeding demands afirm support for the end of the pipe and a proper centering of the same in respect to the cutters m of the die.

Hence I use the die which is illustrated in Figs.

3, 4, and 5, Sheet 2, and which consists of a central ring, G, with two flanges, g and h, one on each side of the ring. The flange g is continuous; but the continuity of the flange his interrupted at intervals by pairs of lugs't'i, three pairs being shown in the present instance, and between each pair of lugs is firmly-bolted a threading-cutter, m. In the interior of the flange g are formed bearings a, concentric with the inner edges of the cutters, and in the interior of the flange h, on each side of the cutters, are formed recesses 10, so as to permit the proper clearance of the tool and prevent clogging by the accumulation ofcuttings. The bearings it serve to insure the proper centering of the pipe, and support and guide the same close up to the cutters. The threadi'ngtool made in this way, moreover, is extremely cheap, as the cutters are simple short pieces of steel whichcan be rapidly and accurately made and effectually hardened, and the cutterholder is a simple casting, in preparing which no elaborate fitting is required.

' A lever, F, having but one roller-carrying arm, may be used instead of the forked lever shown; but the latter is preferred as a medium for imparting amore even pressure'to the ring D.

I claim as my invention- 1. The combination of the fixed casing A and devices for securing a pipe thereto with the die-carrying toothed ring 1), adapted to be 0 rotated, and to slide within and to be guided by the said casing A, and with a lever by which the said ring may be forced into the easing, substantially as set forth.

2. The combination of the casing A, the ro- 5 tating die-carrying ring D, the pinion B, and the forked lever F, having rollersf, as set forth.

3. The within-descril'ied cutting die, having iuternally-projecting cutters m, and internal pipe-supporting bearings a, concentric with and adjacent to the edges of said cutters, as In testimony whereofl have signed my name set forth. to this specification in the presence of two [0 4. The withindescribed cutting-die, the same subscribing witnesses.

consisting of the ring G, having a flange, g, 7 l l 5 for receiving the pipe to be threaded, and a ILLIAM FORBES flange, h, slotted to receive the'cutters, and i Witnesses: having lugs M, between which the cutters are HARRY DRURY,

secured, all substantially as described. HARRY SMITH. 

